Production performance analysis of horizontal drainage wells for the degasification of coal seams
The production performances of horizontal drainage wells for the degasification of coal seams have been investigated with the aid of a multidimensional, two-phase coal seam degasification model. The model is written in rectangular coordinates and can handle a number of horizontal wells and operates in a one-, two-, or three-dimensional mode. The model accommodates multiple horizontal boreholes originating from a common vertical shaft or horizontal boreholes being drilled from the peripheries of the reservoir. In consideration of relatively thin but large lateral extent of coal seams, flow dynamics around a horizontal borehole is described in elliptical flow geometry. The non-linear system of equations generated by the finite difference approximation are solved fully implicitly using Newton's iteration. In the mathematical formulation of the problem, coal seam was treated as a dual-porosity system. Transport of methane in the micropore structure of the coal was described by Fick's Law of diffusion while flow in the more permeable natural fracture network of the coal seam was formulated by Darcy's Law. A quasi-steady state kinetic model was included to represent the desorption of methane from coal grains.
- Research Organization:
- Pennsylvania State Univ.
- OSTI ID:
- 6973366
- Report Number(s):
- CONF-861080-
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
012000 -- Coal
Lignite
& Peat-- Mining
03 NATURAL GAS
030900* -- Natural Gas-- Artificial Stimulation
Plowshare-- (-1989)
ALKANES
BOREHOLES
CAVITIES
COAL DEPOSITS
COAL SEAMS
COMPUTERIZED SIMULATION
CRYSTAL STRUCTURE
DARCY LAW
DEGASSING
DESORPTION
DIFFUSION
FICK LAWS
FINITE DIFFERENCE METHOD
FLOW MODELS
FLUID MECHANICS
GEOLOGIC DEPOSITS
HYDROCARBONS
HYDRODYNAMICS
INCLINATION
INJECTION WELLS
ITERATIVE METHODS
MATHEMATICAL MODELS
MECHANICS
METHANE
MICROSTRUCTURE
MINERAL RESOURCES
NUMERICAL SOLUTION
ORGANIC COMPOUNDS
PERFORMANCE
PERMEABILITY
POROSITY
PRODUCTION
RECOVERY
RESOURCES
SIMULATION
WELLS